It would make a lot of sense to provide an automatic upgrade to versions less than the current. i.e. to 3.2 or 3.3 (or 3.2.1 or 3.3.1 etc.)
Because there's ALWAYS a lag between plugin support for the latest version of WP. And by the time your plugins all have support, WP has a new version! It's a never ending story.
But if I could automatically upgrade to a *slightly* less than current version, then I could regularly upgrade and get the benefit of the new features, security etc. and this cycle of plug-in compatibility lag would be broken.
Right now, I'm stuck on 3.1.2 unless I go through a manual upgrade process, which I'm not confident in doing. i.e. the risk of messing things up by doing it manually is the problem.
I seriously think Automatic should consider it. Even 3.3.x would be a great help if it could be done automatically.